P2 AW55-50 transmission: check your fluid level!

[leapdragon]

Hi all,


Just a note from out of the blue to the cloud, for anyone working on rehabilitating a P2 Volvo and doing transmission stuff.

I've been working on a 2002 V70XC (as my last couple of posts suggest) and had gotten to the point where I was working on the transmission. I did a drain and fill four times over, over the course of a month, and replaced the B2 servo cover. This helped to smooth out some of the shifting, but there was still a harsh shift from 1-2, slight flare 2-3, and a very harsh shift into reverse. I was actively Googling the valve body solenoids and thinking about doing that job.

Now for the important part: do the boring work and CHECK YOUR FLUID LEVEL if you have transmission symptoms.

In my drains-and-fills, I dutifully added back the exact amount that I had drained each time. Before I went ahead and ordered more parts and thought about doing the (for me) tough valve body job, I decided I'd check the fluid condition one more time the easy way. I pulled out the transmission dipstick to wipe on a cloth and at first glance it seemed *very high* (as in, the dipstick was coated with oil inches above the hot range).

I went ahead and warmed the transmission up by driving at highway speeds for 35 miles and came back and checked the fluid level. It was off the charts, even higher than before. Wayyyy too high.

Fast forward to three days and multiple drain-some-drive-and-check cycles and I have removed nearly two quarts from the transmission, 6oz at a time, to get to just about the right fluid level... And here's the kicker—the hard shift from 1-2 is gone, as is the harsh shift into reverse, and what I think was some minor slipping in 4th.

The transmission feels better that it has at any time since I got the vehicle and very nearly as-new. I have no idea which bozo overfilled the transmission on this car so significantly before I bought it, but I've been told that the car was always dealer serviced, and I almost didn't discover it and nearly bought parts that I (most likely) do not need right now. Since I had replaced exactly as much fluid each time as I'd drained, I assumed it was still at the proper level. Not so. Not even ballpark.

There are many posts out there in internet-land saying that the major risk from a surplus fluid level in an automatic transmission is fire or leakage. It would appear that an overfluid situation can lead to some significant shifting and lockup problems as well. So if you're doing a flush or drain-and-fill cycle, be sure to see if your fluid is actually at the right level.

I followed what I've been told are the VADIS instructions to check:

Oil level, checking
Warning! Avoid skin contact with the transmission fluid.
Note! Use only transmission oil, Volvo P/N 116 1540-8 (1 liter container), 116 1640-6 (4 liter container).
Conditions
The difference between the MAX and MIN volumes is 0.2 liters. Check the oil temperature in the transmission.
At room temperature (+20 °C) the oil level is close to the MIN mark on the "cold area".
At room temperature (+20 °C) and low oil level the oil barely reaches the dipstick.
The "cold range" (+40 °C) is reached after approximately 15 minutes idling in the workshop, while the "hot range" (+80 °C) is reached after approximately 30 minutes highway driving at an air temperature above +15 °C.
Note! Carry out the check at an oil temperature of +80 °C. Go to car communication function group 4. Select the digital display parameter. Select the parameter for the transmission oil temperature.
Preparing to check the oil level
Park the car on a level surface.
Apply the parking brake.
Apply the foot brake.
Let the engine idle.
Move the gear selector lever to position P.
Move the gear selector through all positions. Wait in each position for approximately 3 seconds
Move gear selector to position P and wait approximately 2 minutes before checking the oil level.
The dipstick must be pushed down as far as possible into the dipstick tube.
Caution! Wipe the dipstick with a nylon cloth or similar. Do not use a cloth which may leave fluff or threads.

I'm actually still a bit high, about 3/4ths of a centimeter on the dipstick so I'll probably drain another 4 oz. tomorrow and see if I get get it dead on—which will put me at over 2 quarts drained out and not replaced—but I almost hesitate to touch it, it's shifting so perfectly right now. Point being: if you're having shift problems, don't just check fluid, also check fluid quantity.

[vtl]

Overfilled ATF foams, that causes pressure loss. Also different JWS3309-compatible fluids have different heat expansion rates, I know for sure Valvoline MaxLife shrinks a lot at NE winter cold.

[oragex]

The real problem(s) with checking the level on these transmissions are two IMHO: 1.getting the transmission really close to 80C 2.actually 'reading' correctly the dipstick.

Because the transmission fluid is continuously flowing through the radiator, it is hard to estimate when it has actually reached the 80C temp. What's even more annoying, the level on the dipstick varies significantly even for a fluid temperature variation of only 5C. If I remember well, a lecture at a temperature of 75C would cause a level change of near 0.5cm compared with a reading at 80C (there are graphs online about this). I'd rather check it after driving a good hour on city streets (i.e. lower speed thus lower radiator cooling) during hot summer days. I'd totally forget about a lecture in winter days for example. Even better, hook up VIDA and read the exact fluid temp.

Secondly, my main problem is actually the dipstick lecture itself. This dipstick gets smeared with fluid from the tube walls, causing easily a wrong reading. I try to look for the portion of the dipstick with thick fluid on it, i.e. where the fluid looks to have similar to a droplet of fluid at the highest point on the dipstick. Also, it may be better not to read on the first dipstick pull.

[abscate]

Just for calibration of thought...

"The difference between the MAX and MIN volumes is 0.2 liters"

Thats about a small coffee cup full of ATF - not much, so measure carefully.